This can be a gas supply or gas removal device, in which one or more gases can pass from one medium to another medium, or a gas exchanging device, which enables the exchange of one or more gases between two media. Such devices are used in chemistry, biotechnology, and medicine. An important purpose in medicine is the enrichment of a biological liquid—in particular, of blood—with oxygen and/or the removal of carbon dioxide from the liquid—especially, blood. Such measures are necessary, for example, when treating various pulmonary diseases. In addition, such measures may also be necessary, in, for example, in case of acute respiratory failure, as well as for replacing the lung when bypassing it with an extracorporeal circulation, in the mechanical support of the heart, to various degrees, and for being able to operate on a stopped heart.
Moreover, the only long-term effective therapy option for patients with end-stage functional pulmonary disease is the lung transplant. There is no other medical solution for permanently replacing the function of the lungs. For patients who suffer from chronic pulmonary diseases and are not, or not directly, being considered for a lung transplant, there is therefore a need for artificial lung assistance methods.
In order to make possible such a lung assistance method, so-called blood gas exchangers are known from the prior art.
A blood gas exchanger—often also called an oxygenator or artificial lung—is used either to completely take over the lung function short-term during open-heart surgery or to completely or partly support the lung long-term in the intensive care unit. The main function of such a blood gas exchanger consists in the supplying of oxygen to the blood (oxygenation) and in the removal of carbon dioxide from the blood (decarboxylation). The gas exchange takes place, for example, by means of hollow fiber membranes around which blood flows in an extracorporeal gas exchanger, while oxygen-rich or carbon dioxide-poor gas is conducted through the interior of the fiber at the same time. As a result of the concentration difference, oxygen or carbon dioxide can diffuse in a respectively opposite direction through a semi-permeable membrane—generally, a gas-permeable membrane. The fibers can be procured commercially and are delivered, for example, in quadrangular fiber mats or as individual fibers wound on reels.
Two different production methods exist for producing blood gas exchangers from the fiber mats—namely, wound or laid. By way of example, only a fiber mat production based upon the laid variant is to be outlined here, in order to better illustrate the background of the invention.
In the laid variant, the individual fiber mats are layered in a crisscross fashion, which results in a cuboidal—in particular, cubical—package-shaped fiber bundle. The fiber bundle is delimited toward the outside by two covers, which contain the inflow geometry, and by a casting compound. The covers are placed below and above the fiber bundle. The four sides of the fiber bundle are cast on a centrifuge, one side after the other, and connected in this way to the covers. Commercially available gas exchangers produced in this way furthermore have a corresponding cubical cavity, in which the fibers are embedded and in which blood flows around the fibers. The flow generally approaches these gas exchangers at one of the four corners of the fiber bundle or the cavity. The connections for the blood-carrying tubes are in this case oriented orthogonally to the covers of the gas exchanger.
As a result of the size and arrangement of the connections for the blood-carrying tubes, the use of these gas exchangers is, however, limited to stationary applications, in which the patient—awake or sedated—lies in bed. Since patients with chronic pulmonary diseases, who are dependent upon one of these known gas exchangers, are thus considerably limited in their mobility, not just the quality of life of the patients is significantly impaired. Modern therapy approaches, which aim for mobilization of patients, cannot be implemented either.
Known gas exchangers—in particular, gas exchangers intended for use in a heart lung machine (HLM)—are too bulky and too heavy to be carried on the body by a patient, for example. In this respect, the previously common orthogonal orientation of the tubes and connectors of such gas exchanges, which results in a large space requirement for the gas exchanger, is also an argument against such mobile use of a portable gas exchanging device.